Chapter 11 Design, prototyping and construction · Low-fidelity Prototyping •Uses a medium which...

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Design, prototypingand construction

Chapter 11


Overview

• Prototyping and construction

• Conceptual design

• Physical design

• Generating prototypes

• Support for design


Prototyping and construction

• What is a prototype?

• Why prototype?

• Different kinds of prototypinglow fidelityhigh fidelity

• Compromises in prototypingvertical horizontal

• Construction


What is a prototype?

In other design fields a prototype is a small-scale model:

• a miniature car

• a miniature building or town

• the example here comes from a 3D printer


What is a prototype?

In interaction design it can be (among other things):

• a series of screen sketches

• a storyboard, i.e. a cartoon-like series of scenes

• a Powerpoint slide show

• a video simulating the use of a system

• a lump of wood (e.g. PalmPilot)

• a cardboard mock-up

• a piece of software with limited functionality written in the target language or in another language


Why prototype?

• Evaluation and feedback are central to interaction design

• Stakeholders can see, hold, interact with a prototype more easily than a document or a drawing

• Team members can communicate effectively

• You can test out ideas for yourself

• It encourages reflection: very important aspect of design

• Prototypes answer questions, and support designers in choosing between alternatives


Filtering dimensions of prototyping


Manifestation dimensions of prototyping


What to prototype?

• Technical issues

• Work flow, task design

• Screen layouts and information display

• Difficult, controversial, critical areas


Low-fidelity Prototyping

• Uses a medium which is unlike the final medium, e.g. paper, cardboard

• Is quick, cheap and easily changed

• Examples:sketches of screens, task sequences,

etc‘Post-it’ notesstoryboards‘Wizard-of-Oz’


Storyboards

• Often used with scenarios, bringing more detail, and a chance to role play

• It is a series of sketches showing how a user might progress through a task using the device

• Used early in design


Sketching

• Sketching is important to low-fidelity prototyping

• Don’t be inhibited about drawing ability. Practice simple symbols


Card-based prototypes

• Index cards (3 X 5 inches)

• Each card represents one screen or part of screen

• Often used in website development


‘Wizard-of-Oz’ prototyping• The user thinks they are interacting with a

computer, but a developer is responding to output rather than the system.

• Usually done early in design to understand users’ expectations

• What is ‘wrong’ with this approach?

>Blurb blurb

>Do this

>Why?

User


High-fidelity prototyping• Uses materials that you would expect to be in the

final product.

• Prototype looks more like the final system than a

low-fidelity version.

• For a high-fidelity software prototype common

environments include Macromedia Director, Visual

Basic, and Smalltalk.

• Danger that users think they have a full

system…….see compromises


Compromises in prototyping

•All prototypes involve compromises

•For software-based prototyping maybe there is a slow response? sketchy icons? limited functionality?

•Two common types of compromise

• ‘horizontal’: provide a wide range of functions, but with little detail

• ‘vertical’: provide a lot of detail for only a few functions

•Compromises in prototypes mustn’t be ignored. Product needs engineering


Construction

• Taking the prototypes (or learning from

them) and creating a whole

• Quality must be attended to: usability (of

course), reliability, robustness,

maintainability, integrity, portability,

efficiency, etc

• Product must be engineered

Evolutionary prototyping

‘Throw-away’ prototyping


Conceptual design: from requirements to design

• Transform user requirements/needs into a conceptual model

• “a description of the proposed system in terms of a set of integrated ideas and concepts about what it should do, behave and look like, that will be understandable by the users in the manner intended”

• Don’t move to a solution too quickly. Iterate, iterate, iterate

• Consider alternatives: prototyping helps


Is there a suitable metaphor?

• Interface metaphors combine familiar knowledge with new knowledge in a way that will help the user understand the product.

• Three steps: understand functionality, identify potential problem areas, generate metaphors

• Evaluate metaphors:

How much structure does it provide?

How much is relevant to the problem?

Is it easy to represent?

Will the audience understand it?

How extensible is it?


Considering interaction types

• Which interaction type?

How the user invokes actions

Instructing, conversing, manipulating or exploring

• Do different interface types provide insight?

WIMP, shareable, augmented reality, etc


Expanding the conceptual model

• What functions will the product perform?

What will the product do and what will the human do (task allocation)?

• How are the functions related to each other?

Sequential or parallel?

Categorisations, e.g. all actions related to telephone memory storage

• What information needs to be available?

What data is required to perform the task?

How is this data to be transformed by the system?


Using scenarios in conceptual design

• Express proposed or imagined situations

• Used throughout design in various ways

• scripts for user evaluation of

prototypes

• concrete examples of tasks

• as a means of co-operation across

professional boundaries

• Plus and minus scenarios to explore

extreme cases


Generate storyboard from scenario


Generate card-based prototype from use case


Support for design

• Patterns for interaction design

• individual patterns

• pattern languages

• pattern libraries

• Open source systems and components

• Tools and environments


Summary• Different kinds of prototyping are used for different

purposes and at different stages

• Prototypes answer questions, so prototype appropriately

• Construction: the final product must be engineered appropriately

• Conceptual design (the first step of design)

• Consider interaction types and interface types to

prompt creativity

• Storyboards can be generated from scenarios

• Card-based prototypes can be generated from use cases

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